A previously proposed method for obtaining diamond and diamond-like films from hydrocarbons, for example from acetylene, includes the steps of forming an acetylene-oxygen mixture, feeding the mixture under atmospheric pressure to a torch, igniting the oxyacetylene flame and forming a diamond film on a substrate at a rate of 0.003-0.015 micron/sec. This method has been described in J. Appl. Phys. v. 68, N11, 1991, pp. 5941-5943. The disadvantage of this method is the comparatively low rate of formation of the coatings, and also the considerable lack of uniformity in thickness.
Another method that has previously been proposed for obtaining diamond and diamond-like films from a plasma jet has been described in J. Appl. Phys. v. 68, N12, 1990, pp. 6187-6190. This method includes forming a mixture of methane and hydrogen (about 5% methane in hydrogen), and using this mixture as a plasma-forming gas to ignite a plasma jet in a single-jet plasmatron with a tungsten anode and a tantalum cathode at a total pressure in the system of 400 torr. The consumption of the gaseous mixture is 1-2 liters/min and the arc current is equal to 10-12 A at a voltage of 60-90 V. The rate of formation of the films by this method reached 0.06-0.03 micron/sec.
In previously proposed arrangements for obtaining diamond and diamond-like films a plasma reaction zone is formed, a hydrocarbon-hydrogen mixture is then fed to the reaction zone, and a diamond film is obtained on a cooled substrate. The disadvantage of this method is also the relatively low rate of growth of the films, which is reflected in the productivity of the process, particularly when obtaining thick layers.